setErrsVar :: TcRef Messages -> TcRn a -> TcRn a
setErrsVar v = updLclEnv (\ env -> env { tcl_errs = v })
-addErr :: Message -> TcRn ()
+addErr :: Message -> TcRn () -- Ignores the context stack
addErr msg = do { loc <- getSrcSpanM ; addErrAt loc msg }
+failWith :: Message -> TcRn a
+failWith msg = addErr msg >> failM
+
addLocErr :: Located e -> (e -> Message) -> TcRn ()
addLocErr (L loc e) fn = addErrAt loc (fn e)